False ceilings are already known, which comprise, on the one hand, a horizontal frame fixed to the upper part of the walls of a room, this frame being formed by an outer rail, itself constituted by butt-jointed sections, and, on the other hand, a sheet stretched horizontally within this frame, this sheet being constituted by a sheet of plastics material or cloth. The sheet is maintained taut due to the fastening, on the rail, of a border fast with the sheet, forming to some extent a "harpoon", this border presenting in cross section the shape of a hook gripping on a shoulder of the rail.
Heretofore known false ceilings, although they incontestably improve the aesthetics of the rooms in which they are installed, nonetheless present the drawback of leaving visible, all around the room, the lower part of the rail serving for their fastening.
It is an essential object of the present invention to overcome this drawback by providing a false ceiling of which the sheet is fastened to the rail forming support so as totally to hide the fastening rail and considerably to facilitate positioning of the border of the taut sheet on its retaining shoulder.